Soak tamarind for 20 mins minimum in hot water. Extract the pulp and adjust water to 2 cups
Chop peeled onion and garlic into circles.
Grind cleaned coriander leaves with very little water, smoothly.
Heat oil in kadai, temper with mustard, methi seeds, urad dal, toor dal, cumin seeds and curry leaves. Add chopped onion, garlic and fry for 2 minutes in medium flame.
Once garlic is fragrant, add tamarind juice, sambar powder, turmeric, salt and ground coriander leaves.
Adjust water, bring to boil.
Boil until thick (7-8 mins) and add Jaggery. Once dissolved, switch off the stove. Thickens slightly once cooled, so switch off accordingly.